A Plasma Ball (also known as plasma sphere or plasma lamp). Plasma lamps are usually a clear glass orb, filled with a mixture of various gases at low pressure, and driven by high frequency alternating current at high voltage (approx. 35 kHz, 2-5kV), generated by a high voltage transformer. A much smaller orb in its center serves as an electrode. Beams or snakes of 'light' (actually emergent patterns in ionized gas) extend from the inner electrode to the outer glass container, giving an appearance similar to multiple constant beams of coloured lightning. The beams first follow the electric field lines of the dipole, but move up due to convection. Placing a hand near the glass alters the high-frequency electric field, causing a single beam to snake around from the inner ball to the point of contact. An electric current is produced within any conductive object near the orb, as the glass doesn't block the flow of current when high frequencies are involved; the glass acts as the dielectric in a capacitor formed between the ionized gas and the hand.